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			<div>
				<div class="producttitle">
					<span class="productname">Red Hat Enterprise Linux</span> <span
						class="productnumber">6</span>
				</div>
				<div>
					<h1 id="id2177229" class="title">6.1 Release Notes</h1>
				</div>
				<div>
					<h2 class="subtitle">Release Notes for Red Hat Enterprise
						Linux 6.1</h2>
				</div>
				<div>
					<h3 class="corpauthor">
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					<div id="id1442053" class="legalnotice">
						<h1 class="legalnotice">Legal Notice</h1>
						<div class="para">
							Copyright <span class="trademark"></span>© 2011 Red Hat.
						</div>
						<div class="para">
							The text of and illustrations in this document are licensed by
							Red Hat under a Creative Commons Attribution–Share Alike 3.0
							Unported license ("CC-BY-SA"). An explanation of CC-BY-SA is
							available at <a
								href="http://creativecommons.org/licenses/by-sa/3.0/">http://creativecommons.org/licenses/by-sa/3.0/</a>.
							In accordance with CC-BY-SA, if you distribute this document or
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						<div class="para">Red Hat, as the licensor of this document,
							waives the right to enforce, and agrees not to assert, Section 4d
							of CC-BY-SA to the fullest extent permitted by applicable law.</div>
						<div class="para">Red Hat, Red Hat Enterprise Linux, the
							Shadowman logo, JBoss, MetaMatrix, Fedora, the Infinity Logo, and
							RHCE are trademarks of Red Hat, Inc., registered in the United
							States and other countries.</div>
						<div class="para">
							<span class="trademark">Linux</span>® is the registered trademark
							of Linus Torvalds in the United States and other countries.
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				<div>
					<div class="abstract">
						<h6>Abstract</h6>
						<div class="para">
							Red Hat Enterprise Linux minor releases are an aggregation of
							individual enhancement, security and bug fix errata. The Red Hat
							Enterprise Linux 6.1 Release Notes documents the major changes
							made to the Red Hat Enterprise Linux 6 operating system and its
							accompanying applications for this minor release. Detailed notes
							on all changes in this minor release are available in the <a
								href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/index.html">Technical
								Notes</a>.
						</div>
						<div class="para"></div>
					</div>
				</div>
			</div>
			<hr>
		</div>
		<div class="toc">
			<dl>
				<dt>
					<span class="section"><a href="#id1471827">1. Hardware
							Support</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#kernel">2. Kernel</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#desktop">3. Desktop</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#storage">4. Storage</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#interoperability">5.
							Authentication and Interoperability</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#security">6. Security</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#id1507845">7.
							Installation</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#compiler">8. Compiler
							and Tools</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#clustering">9.
							Clustering</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#virtualization">10.
							Virtualization</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#id1435412">11.
							Entitlement</a></span>
				</dt>
				<dt>
					<span class="section"><a href="#id2064680">12. General
							Updates</a></span>
				</dt>
				<dt>
					<span class="appendix"><a
						href="#appe-Publican-Revision_History">A. Revision History</a></span>
				</dt>
			</dl>
		</div>
		<div xml:lang="en-US" class="section" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="id1471827">1.&nbsp;Hardware Support</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1414666">Naming convention for
					network interfaces</h5>
				Traditionally, network interfaces in Linux are named <em
					class="parameter"><code>
						eth<em class="replaceable"><code>[X]</code></em>
					</code></em>. However, in many cases, these names do not correspond to actual
				labels on the chassis. Modern server platforms with multiple network
				adapters can encounter non-deterministic and counterintuitive naming
				of these network interfaces.
			</div>
			<div class="para">
				Red Hat Enterprise Linux 6.1 introduces <span class="application"><strong>biosdevname</strong></span>,
				an optional convention for naming network interfaces. <span
					class="application"><strong>biosdevname</strong></span> assigns
				names to network interfaces based on their physical location. Note,
				however that <span class="application"><strong>biosdevname</strong></span>
				is disabled by default, except for a limited set of Dell systems.
			</div>
			<div class="para">
				Refer to the <a href="https://access.redhat.com/kb/docs/DOC-53612">Red
					Hat Knowledge Base</a> for further information on using <span
					class="application"><strong>biosdevname</strong></span>.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2145635">USB 3.0</h5>
				The implementation of version 3.0 of the Universal Serial Bus (USB
				3.0) specification is a fully supported feature in Red Hat
				Enterprise Linux 6.1. USB 3.0 support was previously considered a
				Technology Preview in previous releases.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1450843">CPU and Memory Hot-add</h5>
				On Nehalem-EX, hot-adding of CPUs and memory is now fully supported
				in Red Hat Enterprise Linux 6.1. Note, however that the hardware
				must also support hot-adding. Damage may occur from an attempt to
				hot-add CPUs or memory on hardware without support for hot-adding.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1425494">Driver Updates</h5>
				Red Hat Enterprise Linux 6.1 features a wide range of driver
				updates, including updates to the following device drivers:
			</div>
			<div class="para">
				<div class="itemizedlist">
					<ul>
						<li class="listitem"><div class="para">
								<code class="filename">ixgbe</code>
								driver for Intel 10 Gigabit PCI Express Network devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">mlx4</code>
								driver for Mellanox ConnectX HCA InfiniBand hardware, providing
								support for Mellanox Connect X2/X3 10GB devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">be2net</code>
								driver for ServerEngines BladeEngine2 10Gbps network devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">bnx2</code>
								driver for Broadcom NetXtreme II network devices, including
								support for Advanced Error Reporting (AER), and PPC support for
								5709 devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">bnx2i</code>
								driver for Broadcom NetXtreme II iSCSI
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">bnx2x</code>
								driver for Broadcom Everest network devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">igbvf</code>
								and
								<code class="filename">ixgbevf</code>
								Virtual Function drivers
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">tg3</code>
								driver for Broadcom Tigon3 ethernet devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">bfa</code>
								driver for Brocade Fibre Channel to PCIe Host Bus Adapters
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">bna</code>
								driver for Brocade 10G PCIe ethernet Controllers
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">cxgb4</code>
								driver for Chelsio Terminator4 10G Unified Wire Network
								controllers
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">be2iscsi</code>
								driver for ServerEngines BladeEngine 2 Open iSCSI devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">be2net</code>
								driver for ServerEngines BladeEngine2 10Gbps network devices
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">lpfc</code>
								driver for Emulex Fibre Channel HBAs
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">e1000</code>
								and
								<code class="filename">e1000e</code>
								drivers for Intel PRO/1000 network devices
							</div></li>
						<li class="listitem"><div class="para">Intel Iron Pond
								ethernet driver</div></li>
						<li class="listitem"><div class="para">Intel Kelsey
								Peak Wireless driver</div></li>
						<li class="listitem"><div class="para">Intel SCU driver
							</div></li>
						<li class="listitem"><div class="para">
								<code class="filename">megaraid_sas</code>
								driver for LSI MegaRAID SAS controllers
							</div></li>
						<li class="listitem"><div class="para">mpt2sas driver
								for the SAS-2 family of adapters from LSI Logic</div></li>
					</ul>
				</div>

			</div>
		</div>
		<div xml:lang="en-US" class="section" id="kernel" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="kernel">2.&nbsp;Kernel</h2>
					</div>
				</div>
			</div>
			<div class="para">
				The kernel shipped in Red Hat Enterprise Linux 6.1 includes several
				hundred bug fixes for and enhancements to the Linux kernel. For
				details concerning every bug fixed in and every enhancement added to
				the kernel for this release, refer to the kernel chapter in the <a
					href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/index.html">Red
					Hat Enterprise Linux 6.1 Technical Notes.</a>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1425975">Control Groups</h5>
				Control groups are a feature of the Linux kernel introduced in Red
				Hat Enterprise Linux 6. Each control group is a set of tasks on a
				system that have been grouped together to better manage their
				interaction with system hardware. Control groups can be tracked to
				monitor the system resources that they use. Additionally, system
				administrators can use control group infrastructure to allow or to
				deny specific control groups access to system resources such as
				memory, CPUs (or groups of CPUs), networking, I/O, or the scheduler.
			</div>
			<div class="para">Red Hat Enterprise Linux 6.1 introduces many
				improvements and updates to control groups, including the ability to
				throttle block device Input/Output (I/O) to a particular device,
				either by bytes per second or I/O Per Second (IOPS).</div>
			<div class="para">
				Additionally, integration with libvirt and other userspace tools is
				provided by the new ability to create hierarchical block device
				control groups. The new block device control group tunable <em
					class="parameter"><code>group_idle</code></em>, provides better
				throughput with control groups while maintaining fairness.
			</div>
			<div class="para">
				Red Hat Enterprise Linux 6.1 also introduces the new <span
					class="application"><strong>autogroup</strong></span> feature,
				reducing latencies and allowing for more interactive tasks during
				CPU intensive workloads. This <span class="application"><strong>cgsnapshot</strong></span>
				tool, providing the ability to take a snapshot of the current
				control group configuration.
			</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						Control Groups and other resource management features are
						discussed in detail in the Red Hat Enterprise Linux 6 <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Resource_Management_Guide/index.html">Resource
							Management Guide</a>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1448116">Networking updates</h5>
				Red Hat Enterprise Linux 6.1 introduces support for Receive Packet
				Steering (RPS) and Receive Flow Steering (RFS). Receive Packet
				Steering allows incoming network packets to be processed in parallel
				over multiple CPU cores. Receive Flow Steering chooses the optimal
				CPU to process network data intended for a specific application.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1472992">kdump</h5>
				kdump is an advanced crash dumping mechanism. When enabled, the
				system is booted from the context of another kernel. This second
				kernel reserves a small amount of memory, and its only purpose is to
				capture the core dump image in case the system crashes.
			</div>
			<div class="para">Red Hat Enterprise Linux 6.1 introduces the
				kernel message dumper, which is called when a kernel panic occurs.
				The kernel message dumper provides easier crash analysis and allows
				3rd party kernel message logging to alternative targets.</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2015568">Performance updates and
					improvements</h5>
				The kernel in Red Hat Enterprise Linux 6.1 provides the following
				notable performance improvements:
				<div class="itemizedlist">
					<ul>
						<li class="listitem"><div class="para">Updates and
								improvements to Transparent Huge Pages (THP) support</div></li>
						<li class="listitem"><div class="para">
								Updates to <span class="application"><strong>perf_event</strong></span>,
								adding the new <span class="application"><strong>perf
										lock</strong></span> feature to better analyze lock events.
							</div></li>
						<li class="listitem"><div class="para">
								<span class="application"><strong>kprobes</strong></span> jump
								optimization, reducing overhead and enhancing SystemTap
								performance.
							</div></li>
						<li class="listitem"><div class="para">
								Updates to <span class="application"><strong>i7300_edac</strong></span>
								and <span class="application"><strong>i7core_edac</strong></span>,
								providing support for monitoring of memory errors on
								motherboards using Intel 7300 chipset
							</div></li>
					</ul>
				</div>

			</div>
		</div>
		<div xml:lang="en-US" class="section" id="desktop" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="desktop">3.&nbsp;Desktop</h2>
					</div>
				</div>
			</div>
			<div class="formalpara" id="graphics-hardware">
				<h5 class="formalpara">Graphics Hardware</h5>
				Red Hat Enterprise Linux 6.1 provides a range of updates for
				graphics hardware. The driver for Intel Generation 6 Graphics on the
				Sandy Bridge processor is introduced in this release, providing
				fully accelerated 2D and 3D graphics on these devices. Additionally,
				this release introduces support for the Matrox MGA-G200ER graphics
				chipset.
			</div>
			<div class="para">
				Red Hat Enterprise Linux 6.1 introduces the
				<code class="filename">xorg-x11-drv-xgi</code>
				video driver to support the XGI Z9S AND Z11 chipsets. The SIS driver
				that provided support for older XGI hardware is no longer being
				updated to support new hardware.
			</div>
			<div class="para">Monitors that do not supply Extended Display
				Identification Data (EDID) to the operating system now have a
				default resolution of 1024 x 768 pixels.</div>
			<div class="formalpara" id="network-manager">
				<h5 class="formalpara">Network Manager</h5>
				NetworkManager is the desktop tool that is used to set up, configure
				and manage a wide range of network connection types. In Red Hat
				Enterprise Linux 6.1, NetworkManager has improved support for the
				configuration of Wi-Fi Protected Access (WPA) Enterprise and
				Internet Protocol version 6 (IPv6).
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1472107">Audio</h5>
				Red Hat Enterprise Linux 6.1 provides updated Advanced Linux Sound
				Architecture - High Definition Audio (ALSA-HDA) drivers.
			</div>
		</div>
		<div xml:lang="en-US" class="section" id="storage" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="storage">4.&nbsp;Storage</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1415981">LVM Snapshots of Mirrors</h5>
				The LVM snapshot feature provides the ability to create backup
				images of a logical volume at a particular instant without causing a
				service interruption. When a change is made to the original device
				(the origin) after a snapshot is taken, the snapshot feature makes a
				copy of the changed data area as it was prior to the change so that
				it can reconstruct the state of the device. In Red Hat Enterprise
				Linux 6.1 the ability to take a snapshot of a mirrored logical
				volume is a fully supported feature.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2015141">LVM Stripe of Mirrors</h5>
				It is now possible to combine RAID0 (striping) and RAID1 (mirroring)
				in a single logical volume in LVM. Creating a logical volume while
				simultaneously specifying the number of mirrors ('--mirrors X') and
				the number of stripes ('--stripes Y') results in a mirror devices
				whose constituent devices are striped.
			</div>
		</div>
		<div xml:lang="en-US" class="section" id="interoperability"
			lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="interoperability">5.&nbsp;Authentication
							and Interoperability</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1474049">System Security Services
					Daemon (SSSD)</h5>
				The System Security Services Daemon (SSSD) implements a set of
				services for central management of identity and authentication.
				Centralizing identity and authentication services enables local
				caching of identities, allowing users to still identify in cases
				where the connection to the server is interrupted. SSSD supports
				many types of identity and authentication services, including: Red
				Hat Directory Server, OpenLDAP, 389, Kerberos and LDAP. SSSD in Red
				Hat Enterprise Linux 6.1 is updated to version 1.5, providing the
				following bug fixes and enhancements:
			</div>
			<div class="itemizedlist">
				<ul>
					<li class="listitem"><div class="para">Netgroups support
						</div></li>
					<li class="listitem"><div class="para">Improved
							online/offline detection</div></li>
					<li class="listitem"><div class="para">Improved LDAP
							access-control provider with support for shadow and
							authorizedService</div></li>
					<li class="listitem"><div class="para">Improved caching
							and cleanup logic for different schemata</div></li>
					<li class="listitem"><div class="para">Improved DNS
							based discovery</div></li>
					<li class="listitem"><div class="para">Automatic
							Kerberos ticket renewal</div></li>
					<li class="listitem"><div class="para">Enablement of the
							Kerberos FAST protocol</div></li>
					<li class="listitem"><div class="para">Better handling
							of password expiration</div></li>
				</ul>
			</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/chap-SSSD_User_Guide-Introduction.html">Deployment
							Guide</a> contains a section that describes how to install and
						configure SSSD.
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2141886">IPA</h5>
				Red Hat Enterprise Linux 6.1 features IPA as a Technology Preview.
				IPA is an integrated security information management solution which
				combines Red Hat Enterprise Linux, Red Hat Directory Server, MIT
				Kerberos, and NTP. It provides web browser and command-line
				interfaces, and its numerous administration tools allow an
				administrator to quickly install, set up, and administer one or more
				servers for centralized authentication and identity management.
			</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Enterprise_Identity_Management_Guide/index.html">Enterprise
							Identity Management Guide</a> contains further information on the IPA
						Technology Preview.
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2141858">Samba</h5>
				Samba is an open source implementation of the Common Internet File
				System (CIFS) protocol. It allows the networking of Microsoft
				Windows, Linux, UNIX, and other operating systems together, enabling
				access to Windows-based file and printer shares. Samba in Red Hat
				Enterprise Linux 6.1 is updated to version 3.5.6.
			</div>
			<div class="para">Samba in Red Hat Enterprise Linux 6.1 allows
				users to use their own Kerberos credentials when accessing CIFS
				mount, rather than needing the same mount credentials for all access
				to the mount.</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1445926">FreeRADIUS</h5>
				FreeRADIUS is an Internet authentication daemon, which implements
				the RADIUS protocol, as defined in RFC 2865 (and others). It allows
				Network Access Servers (NAS boxes) to perform authentication for
				dial-up users. FreeRADIUS in Red Hat Enterprise Linux 6.1 is updated
				to version 2.1.10.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1445940">Kerberos</h5>
				Kerberos is a networked authentication system which allows users and
				computers to authenticate to each other with the help of a trusted
				third party, the KDC. In Red Hat Enterprise Linux 6.1, Kerberos
				(supplied by the krb5 package) is updated to version 1.9.
			</div>
		</div>
		<div xml:lang="en-US" class="section" id="security" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="security">6.&nbsp;Security</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1782870">OpenSCAP</h5>
				OpenSCAP is a set of open source libraries that support the Security
				Content Automation Protocol (SCAP) standards from the National
				Institute of Standards and Technology (NIST). OpenSCAP supports the
				SCAP components:
				<div class="itemizedlist">
					<ul>
						<li class="listitem"><div class="para">Common
								Vulnerabilities and Exposures (CVE)</div></li>
						<li class="listitem"><div class="para">Common Platform
								Enumeration (CPE)</div></li>
						<li class="listitem"><div class="para">Common
								Configuration Enumeration (CCE)</div></li>
						<li class="listitem"><div class="para">Common
								Vulnerability Scoring System (CVSS)</div></li>
						<li class="listitem"><div class="para">Open
								Vulnerability and Assessment Language (OVAL)</div></li>
						<li class="listitem"><div class="para">Extensible
								Configuration Checklist Description Format (XCCDF)</div></li>
					</ul>
				</div>
				Additionally, the openSCAP package includes an application to
				generate SCAP reports about system configuration. openSCAP is now a
				fully supported package in Red Hat Enterprise Linux 6.1.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1472042">Smartcard support for
					SPICE</h5>
				The Simple Protocol for Independent Computing Environments (SPICE)
				is a remote display protocol designed for virtual environments.
				SPICE users can view a virtualized desktop or server from the local
				system or any system with network access to the server. Red Hat
				Enterprise Linux 6.1 introduces support for smartcard passthough via
				the SPICE protocol.
			</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/">Security
							Guide</a> assists users and administrators in learning the processes
						and practices of securing workstations and servers against local
						and remote intrusion, exploitation and malicious activity.
					</div>
				</div>
			</div>
		</div>
		<div xml:lang="en-US" class="section" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="id1507845">7.&nbsp;Installation</h2>
					</div>
				</div>
			</div>
			<div class="para">Installation and boot support is added in Red
				Hat Enterprise Linux 6.1 for the Emulex 10GbE PCI-E Gen2 and Chelsio
				T4 10GbE network adapters. Additionally, the GRUB bootloader is
				updated with support for booting volumes with a 4KB sector size on
				UEFI systems.</div>
			<div class="para">
				The installer in Red Hat Enterprise Linux 6.1 will detect
				unsupported hardware platforms and provide a notification to the
				user. The installation will continue, but the following message is
				displayed
				<pre class="screen">This hardware (or a combination thereof) is not supported by Red Hat. For more information on supported hardware, please refer to http://www.redhat.com/hardware.

</pre>

			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2142461">Improved support for
					iSCSI adapters</h5>
				Red Hat Enterprise Linux 6.1 features improved support for iSCSI
				adapters at installation and boot time, including the ability to
				separate login credentials for iSCSI storage during installation and
				support for offload iSCSI adapters (e.g. the Emulex Tiger Shark
				adapter).
			</div>
			<div class="para">Red Hat Enterprise Linux 6 supports
				installation over iSCSI using auto-detection of BIOS iSCSI settings
				in iBFT. However, reconfiguration of the iBFT settings after
				installation was not possible. In Red Hat enterprise Linux 6.1,
				TCP/IP settings and iSCSI initiator configuration are dynamically
				configured from iBFT settings during boot time.</div>
		</div>
		<div xml:lang="en-US" class="section" id="compiler" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="compiler">8.&nbsp;Compiler and Tools</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1425495">SystemTap</h5>
				SystemTap is a tracing and probing tool that allows users to study
				and monitor the activities of the operating system (particularly,
				the kernel) in fine detail. It provides information similar to the
				output of tools like netstat, ps, top, and iostat; however,
				SystemTap is designed to provide more filtering and analysis options
				for collected information.
			</div>
			<div class="para">SystemTap in Red Hat Enterprise Linux 6.1 is
				updated to version 1.4, providing:</div>
			<div class="itemizedlist">
				<ul>
					<li class="listitem"><div class="para">Alpha version of
							remote host scripting with --remote USER@HOST</div></li>
					<li class="listitem"><div class="para">Optimization of
							near zero cost for dormant user probe points</div></li>
				</ul>
			</div>
			<div class="para">
				Refer to the <a
					href="http://sourceware.org/ml/systemtap/2011-q1/msg00036.html">SystemTap
					Release Notes</a> for more information.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2145522">GNU Project Debugger
					(GDB)</h5>
				The GNU Project Debugger (normally referred to as GDB) debugs
				programs written in C, C++, and other languages by executing them in
				a controlled fashion, and then printing out their data. GDB in Red
				Hat Enterprise Linux 6.1 is updated to version 7.2, providing many
				bugfixes and enhancements, including enhancements to the python
				scripting features, and C++ debugging enhancements.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1471864">Performance Application
					Programming Interface (PAPI)</h5>
				Red Hat Enterprise Linux 6.1 introduces the Performance Application
				Programming Interface (PAPI). PAPI is a specification of a
				cross-platform interfaces to hardware performance counters on modern
				microprocessors. These counters exist as a small set of registers
				that count events, which are occurrences of specific signals related
				to a processor's function. Monitoring these events has a variety of
				uses in application performance analysis and tuning.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1535250">OProfile</h5>
				OProfile is a system-wide profiler for Linux systems. The profiling
				runs transparently in the background and profile data can be
				collected at any time. In Red Hat Enterprise Linux 6.1, OProfile is
				updated to version 0.9.6-12, providing support for AMD family
				12h/14h/15h processors and Intel Westmere specific events.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1438071">Valgrind</h5>
				Valgrind is an instrumentation framework for building dynamic
				analysis tools that can be used to profile applications in detail.
				Valgrind tools are generally used to automatically detect many
				memory management and threading problems. The Valgrind suite also
				includes tools that allow you to build new profiling tools to suit
				your needs.
			</div>
			<div class="para">Red Hat Enterprise Linux 6.1 provides
				Valgrind version 3.6.0.</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1538826">GNU Compiler Collection
					(GCC)</h5>
				The GNU Compiler Collection (GCC) includes, among others, C, C++,
				and Java GNU compilers and related support libraries. Red Hat
				Enterprise Linux 6 features version 4.4 of GCC, which includes the
				following features and enhancements:
				<div class="itemizedlist">
					<ul>
						<li class="listitem"><div class="para">IBM z196 new
								instruction support and optimizations</div></li>
						<li class="listitem"><div class="para">IBM z10 prefetch
								instruction support and optimizations</div></li>
					</ul>
				</div>

			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1538568">libdfp</h5>
				The libdfp library is updated in Red Hat Enterprise Linux 6.1.
				libdfp is a decimal floating point math library, and is available as
				an alternative to the glibc math functions on Power and s390x
				architectures, and is available in the supplementary channels.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1538582">Eclipse</h5>
				Eclipse is a powerful development environment that provides tools
				for each phase of the development process. It is integrated into a
				single, fully configurable user interface for ease of use, featuring
				a pluggable architecture which allows for extension in a variety of
				ways.
			</div>
			<div class="para">An updated version of the Eclipse development
				environment is available in Red Hat Enterprise Linux 6.1, providing
				the following updates and enhancements:</div>
			<div class="itemizedlist">
				<ul>
					<li class="listitem"><div class="para">All the major
							plugins are refreshed, including Valgrind and OProfile
							integration and the tools for working with C and C++</div></li>
					<li class="listitem"><div class="para">The Mylyn
							task-focused framework is updated</div></li>
					<li class="listitem"><div class="para">Enhanced resource
							filtering for workspace contents</div></li>
					<li class="listitem"><div class="para">performance
							enhancements when working with C, C++ and Java code bases</div></li>
				</ul>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1465509">IcedTea</h5>
				New IcedTea Web Open Source Web Browser Plugin and Webstart
				implementation for OpenJDK.
			</div>
			<div class="itemizedlist">
				<ul>
					<li class="listitem"><div class="para">Allows browsers
							such as Firefox to load Java applets embedded in a web page</div></li>
					<li class="listitem"><div class="para">Provides
							framework to launch JNLP (Java Network Launching Protocol) files
						</div></li>
				</ul>
			</div>
		</div>
		<div xml:lang="en-US" class="section" id="clustering" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="clustering">9.&nbsp;Clustering</h2>
					</div>
				</div>
			</div>
			<div class="para">Clusters are multiple computers (nodes)
				working in concert to increase reliability, scalability, and
				availability to critical production services. High Availability
				using Red Hat Enterprise Linux 6 can be deployed in a variety of
				configurations to suit varying needs for performance,
				high-availability, load balancing, and file sharing.</div>
			<div class="para">The following major updates to clustering are
				available in Red Hat Enterprise Linux 6.1</div>
			<div class="itemizedlist">
				<ul>
					<li class="listitem"><div class="para">Rgmanager now
							supports the concept of critical and non-critical resources</div></li>
					<li class="listitem"><div class="para">System
							Administrators can now configure and run a cluster using command
							line tools. This feature provides an alternative to manually
							editing the cluster.conf configuration file or using the
							graphical configuration tool, Luci.</div></li>
					<li class="listitem"><div class="para">Red Hat
							Enterprise Linux High Availability on Red Hat Enterprise Linux
							KVM hosts is fully supported</div></li>
					<li class="listitem"><div class="para">Comprehensive
							SNMP Trap support from central cluster daemons and sub-parts</div></li>
					<li class="listitem"><div class="para">Additional
							watchdog integration allows a node to reboot itself when it loses
							quorum</div></li>
				</ul>
			</div>
			<div class="para">The development library packages provided in
				the High Availability, Load Balancer, and Resilient Storage Add-On
				channels are not considered supported nor are their ABIs or APIs
				guaranteed to be consistent.</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/High_Availability_Add-On_Overview/index.html">Cluster
							Suite Overview</a> document provides an overview of Red Hat Cluster
						Suite for Red Hat Enterprise Linux 6. Additionally, the <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Cluster_Administration/index.html">High
							Availability Administration</a> document describes the configuration
						and management of Red Hat cluster systems for Red Hat Enterprise
						Linux 6.
					</div>
				</div>
			</div>
		</div>
		<div xml:lang="en-US" class="section" id="virtualization" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="virtualization">10.&nbsp;Virtualization</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1439156">vhost</h5>
				The new host kernel networking backend, <span class="application"><strong>vhost</strong></span>,
				is a fully supported feature in Red Hat Enterprise Linux 6.1. <span
					class="application"><strong>vhost</strong></span> provides superior
				throughput and latency over the userspace implementation.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1760114">qcow2</h5>
				The qcow2 image format now supports caching of metadata.
				Additionally, support is added for live snapshots using external
				qcow2 images.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1430294">Block I/O latency
					improvements</h5>
				<span class="application"><strong>ioeventfd</strong></span> is now
				available, providing faster notification of block I/O.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1435056">Kernel SamePage Merging
					(KSM)</h5>
				The KVM hypervisor in Red Hat Enterprise Linux 6 features Kernel
				SamePage Merging (KSM), allowing KVM guests to share identical
				memory pages. Page sharing reduces memory duplication, allowing a
				host with similar guest operating systems to run more efficiently.
			</div>
			<div class="para">KSM in Red Hat Enterprise Linux 6.1 is
				Transparent HugePage aware. KSM has the ability to scan subpages
				inside hugepages and split them when merging is possible.</div>
			<div class="para">Additionally, KSM enablement can now be
				controlled on a per-VM basis.</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1449146">PCI device assignment
					improvements</h5>
				PCI configuration space access is improved, enabling a broader set
				of PCI devices to be device-assigned to guest VMs.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1451609">KVMClock Improvements</h5>
				In Red Hat Enterprise Linux 6.1, the Time Stamp Counter (TSC)
				synchronization can now be automatically detected on guest bootup or
				when a host CPU is hot-plugged. Additionally, the TSC
				synchronization frequency is adjusted after a live migration.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2148497">QEMU monitor</h5>
				Additionally, the new
				<code class="command">drive_del</code>
				command allows libvirt to safely remove a block device from a guest.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1439712">General Updates and
					Improvements</h5>
				<div class="itemizedlist">
					<ul>
						<li class="listitem"><div class="para">The maximum
								display resolution on qemu-kvm is now 2560x1600 pixels</div></li>
						<li class="listitem"><div class="para">Red Hat
								Enterprise Linux 6.1 includes the ability to expose an emulated
								Intel HDA sound card to all guests. This update enables native
								sound support for many guests including the 64-bit version of
								Windows 7</div></li>
						<li class="listitem"><div class="para">QEMU char device
								flow control is enabled</div></li>
						<li class="listitem"><div class="para">Message Signaled
								Interrupts (MSI) implemented for the win-virtio-blk driver</div></li>
						<li class="listitem"><div class="para">A new standard
								interface for selecting/prioritizing the boot devices of the
								guest</div></li>
						<li class="listitem"><div class="para">Stability
								improvements for live migration</div></li>
						<li class="listitem"><div class="para">QEMU userspace
								static tracing</div></li>
						<li class="listitem"><div class="para">Virtual disk
								online dynamic resize feature</div></li>
						<li class="listitem"><div class="para">Forbid pci hot
								unplug of critical devices such as gpu, pci bus controller, isa
								bus controller</div></li>
					</ul>
				</div>

			</div>
		</div>
		<div xml:lang="en-US" class="section" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="id1435412">11.&nbsp;Entitlement</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1758264">Red Hat Subscription
					Manager and the Subscription Service</h5>
				Effective software and infrastructure management requires a
				mechanism to handle the software inventory — both the type of
				products and the number of systems that the software is installed
				on. In parallel with Red Hat Enterprise Linux 6.1, Red Hat is
				introducing a new subscription service which provides oversight for
				the software subscriptions for an organization and a more effective
				content delivery system.
			</div>
			<div class="para">On local systems, the new Red Hat
				Subscription Manager offers both GUI and command-line tools to
				manage the local system and its allocated subscriptions. A better
				method to handle subscriptions will help our customers allocate
				their subscriptions more effectively and will make installing and
				updating Red Hat products much simpler.</div>
			<div class="para">
				In Red Hat Enterprise Linux 6.0 and 5.6 and older, subscriptions
				were based on <span class="emphasis"><em>access to
						channels</em></span> and were assigned to an organization as a whole. Starting
				in Red Hat Enterprise Linux 6.1, subscriptions are based on <span
					class="emphasis"><em>installed products</em></span> and are
				assigned to systems individually. This provides clear and delineated
				control over the products used by and subscribed to by a specific
				system.
			</div>
			<div class="para">As part of the new subscription structure,
				the Customer Portal provides two paths to manage subscriptions:
				Certificate-based Red Hat Network, which uses the new subscription
				service, and RHN Classic, which uses the traditional channels.
				Systems must be managed either by the new Certificate-based Red Hat
				Network or by RHN Classic, but not both.</div>
			<div class="para">If a system was previously managed by RHN
				Classic, there is no direct, supported migration path from RHN
				Classic to Certificate-based Red Hat Network.</div>
			<div class="note">
				<div class="admonition_header">
					<h2>Further Reading</h2>
				</div>
				<div class="admonition">
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/entitlements.html">Red
							Hat Enterprise Linux 6.1 Deployment Guide</a> contains further
						information on managing subscriptions.
					</div>
					<div class="para">
						The <a
							href="http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Installation_Guide/sn-firstboot-updates.html">Red
							Hat Enterprise Linux 6.1 Installation Guide</a> contains further
						information on the registration and subscription process during
						firstboot and kickstart.
					</div>
				</div>
			</div>
		</div>
		<div xml:lang="en-US" class="section" lang="en-US">
			<div class="titlepage">
				<div>
					<div>
						<h2 class="title" id="id2064680">12.&nbsp;General Updates</h2>
					</div>
				</div>
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1464469">Automated Bug Reporting
					Tool</h5>
				Red Hat Enterprise Linux 6 introduced the new Automated Bug
				Reporting Tool (ABRT). ABRT logs details of software crashes on a
				local system, and provides interfaces (both graphical and command
				line based) to report issues to Red Hat support. In Red Hat
				Enterprise Linux 6.1, ABRT is updated to version 1.1.16. This update
				provides an enhanced graphical user interface (GUI) in addition to a
				range of other bugfixes and enhancements.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1428422">openCryptoki</h5>
				openCryptoki contains version 2.11 of the PKCS#11 API, implemented
				for IBM Cryptocards. openCryptoki is updated in Red Hat Enterprise
				Linux 6.1, providing many bugfixes and enhancements, including
				better overall performance.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1425657">OpenLDAP</h5>
				OpenLDAP is an open source suite of Lightweight Directory Access
				Protocol (LDAP) applications and development tools. OpenLDAP in Red
				Hat Enterprise Linux 6.1 is updated to version 2.4.23. This updated
				version of OpenLDAP utilizes Network Security Services (NSS)
				cryptographic libraries, replacing OpenSSL.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id2135000">TigerVNC</h5>
				TigerVNC provides client and server software for Virtual Network
				Computing (VNC). VNC is a remote display system, allowing a user to
				view a computing desktop environment over a network
				connection.TigerVNC is updated to version 1.1.0, providing many
				bugfixes enhanced encryption support.
			</div>
			<div class="formalpara">
				<h5 class="formalpara" id="id1450251">tuned</h5>
				tuned is a system tuning daemon that monitors system components and
				dynamically tunes system settings. Utilizing ktune (the static
				mechanism for system tuning), tuned can monitor and tune devices
				(e.g. hard disk drives and ethernet devices). In Red Hat Enterprise
				Linux 6.1, the tuned tuning profiles now include support for the
				s390x architectures.
			</div>
		</div>
		<div xml:lang="en-US" class="appendix"
			id="appe-Publican-Revision_History" lang="en-US">
			<h2 class="title">A.&nbsp;Revision History</h2>
			<div class="para">
				<div class="revhistory">
					<table summary="Revision history" border="0" width="100%">
						<tbody>
							<tr>
								<th colspan="3" align="left" valign="top"><strong>Revision
										History</strong></th>
							</tr>
							<tr>
								<td align="left">Revision 0-39</td>
								<td align="left">Fri May 20 2011</td>
								<td align="left"><span class="author"><span
										class="firstname">Ryan</span> <span class="surname">Lerch</span></span></td>
							</tr>
							<tr>
								<td colspan="3" align="left">
									<table summary="Simple list" class="simplelist" border="0">
										<tbody>
											<tr>
												<td>Copyedit in the Installation section</td>
											</tr>
										</tbody>
									</table>
								</td>
							</tr>
							<tr>
								<td align="left">Revision 1-0</td>
								<td align="left">Tue Mar 22 2011</td>
								<td align="left"><span class="author"><span
										class="firstname">Ryan</span> <span class="surname">Lerch</span></span></td>
							</tr>
							<tr>
								<td colspan="3" align="left">
									<table summary="Simple list" class="simplelist" border="0">
										<tbody>
											<tr>
												<td>Initial Version of the Red Hat Enterprise Linux 6.1
													Release Notes</td>
											</tr>
										</tbody>
									</table>
								</td>
							</tr>
						</tbody>
					</table>
				</div>
			</div>
		</div>
	</div>
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